Page 8 of 8 FirstFirst ... 678
Results 71 to 79 of 79

Thread: Can't find actual codes against this

  1. #71
    Join Date
    Jan 2007
    Posts
    2,748
    Quote Originally Posted by kwired View Post
    if you sent out the six ungrounded conductors (but connected to three overcurrent devices - one each phase) and returned with 5 ungrounded conductors

    What ?

    JAP>

  2. #72
    Join Date
    Feb 2003
    Location
    Pennsylvania
    Posts
    2,066
    If ground fault protection (3-pole) was added to this circuit, the circuit protection would trip unless the neutral one and seven landed on the breakers neutral terminal and a single pigtail from the breakers supply neutral landed on the panel neutral buss.

    With both neutral 1 and 7 tied to a multi wire circuit and landing separately onto the panels neutral buss i do not know how to define this circuit.

    I really don't have much more to add constructively to the discussion
    Attached Images Attached Images  

  3. #73
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    32,914
    Quote Originally Posted by david View Post
    If ground fault protection (3-pole) was added to this circuit, the circuit protection would trip unless the neutral one and seven landed on the breakers neutral terminal and a single pigtail from the breakers supply neutral landed on the panel neutral buss.

    With both neutral 1 and 7 tied to a multi wire circuit and landing separately onto the panels neutral buss i do not know how to define this circuit.

    I really don't have much more to add constructively to the discussion
    Do you call it a MWBC if we tied those two neutrals together just an inch or two away from the panelboard neutral bus and only landed one common "wire" on the bus?

    I do not see "neutral bus" anywhere in the definition of "Branch circuit, multiwire". It does say "neutral or grounded conductor of the system" which is exactly what the neutral bus in the panel is a part of.

  4. #74
    Join Date
    Jan 2007
    Posts
    2,748
    The same could be said if you had a single pole circuit going out feeding 2 individual receptacles where each receptacle had it's own neutral back to the neutral bar in the panel.

    No, the return current on receptacle #1 would not return on the Neutral from #2 receptacle,
    and,
    No, the return current on receptacle #2 would not return on the Neutral from #1 receptacle,

    If we were to put a GFI ahead of this circuit, we would have to take both return neutrals and land them on the neutral terminal of the GFI breaker, but, since the terminal is probably only rated for 1 conductor, we'd probably have to take the 2 neutrals off of the neutral bar, wirenut the 2 neutrals together in the panel, and bring only 1 conductor to the neutral termination on the breaker.

    Dad Gum those maintenance guys for making us have to think about this so much.

    JAP>

  5. #75
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    32,914
    Quote Originally Posted by jap View Post
    The same could be said if you had a single pole circuit going out feeding 2 individual receptacles where each receptacle had it's own neutral back to the neutral bar in the panel.

    No, the return current on receptacle #1 would not return on the Neutral from #2 receptacle,
    and,
    No, the return current on receptacle #2 would not return on the Neutral from #1 receptacle,

    If we were to put a GFI ahead of this circuit, we would have to take both return neutrals and land them on the neutral terminal of the GFI breaker, but, since the terminal is probably only rated for 1 conductor, we'd probably have to take the 2 neutrals off of the neutral bar, wirenut the 2 neutrals together in the panel, and bring only 1 conductor to the neutral termination on the breaker.

    Dad Gum those maintenance guys for making us have to think about this so much.

    JAP>
    Correct - but you still consider there to be only 1 branch circuit in that situation.


    Run a 400 amp feeder with 500 copper on A phase, parallel 4/0 alumium on B phase, parallel 3/0 copper on C phase, and three parallel 1/0 aluminum as the neutral - you still have just one feeder, yes?

  6. #76
    Join Date
    Jan 2007
    Posts
    2,748
    Quote Originally Posted by kwired View Post
    Correct - but you still consider there to be only 1 branch circuit in that situation.


    Run a 400 amp feeder with 500 copper on A phase, parallel 4/0 alumium on B phase, parallel 3/0 copper on C phase, and three parallel 1/0 aluminum as the neutral - you still have just one feeder, yes?
    Yes, but lets try to stay focused K-Wired...

    JAP>

  7. #77
    Join Date
    Dec 2007
    Location
    NE Nebraska
    Posts
    32,914
    Quote Originally Posted by jap View Post
    Yes, but lets try to stay focused K-Wired...

    JAP>
    Sorry, a little bored today, since the ice storm has finally moved into my area, I planned to work in the office today, chatting here is much more fun then office work though

  8. #78
    Join Date
    Jun 2013
    Location
    Massachusetts
    Posts
    24
    Quote Originally Posted by charlie b View Post
    I am not sure I fully understand the configuration you are describing. It sounds like you originally had two MWBCs: 1-3-5 and 7-9-11. It also sounds like the loads previously served by 1, 3, 5, and 7 are now getting their power from circuit breaker #1. That much is OK. Finally, it also sounds like circuits 9 and 11 still comprise a MWBC, and that they still share the original neutral. That much is also OK. But I can’t envision what happened to the neutral connection at the receptacle originally fed from circuit 7.

    There was a hot wire from circuit breaker 7 that landed on the hot side of a receptacle outlet (call it “receptacle #7”). There was a neutral wire that connected the neutral side of that receptacle to the neutral sides of the receptacle #9 and receptacle #11. From some point along the way, one neutral wire made its way back to the panel’s neutral bus. But if all the wiring changes were done inside the panel, then receptacle #7 still shares its neutral with receptacles 9 and 11. If that is the case, then even if circuit breakers 9 and 11 share a listed handle tie, any future work on one of these circuits would place the worker in danger, because the worker would not know that they also need to turn off circuit breaker #1. You would have a violation of 300.3(B).

    Wouldn’t tying CKT’s 1,3,5,7 together sharing a neutral be a violation since CKT 1 and 7 share the same phase?

  9. #79
    Join Date
    Dec 2012
    Location
    Placerville, CA, USA
    Posts
    17,958
    Quote Originally Posted by lordofthisworld View Post
    Wouldn’t tying CKT’s 1,3,5,7 together sharing a neutral be a violation since CKT 1 and 7 share the same phase?
    No, because the circuit originally on breaker 1 is now fed from breaker 7. As long as the load calculations are OK the fact that both circuits are connected to #7 is not, by itself, a problem.
    If both 1 and 7 had been fully (or even just above half) loaded, it would indeed be a problem.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •